21433233281 has 2 divisors, whose sum is σ = 21433233282. Its totient is φ = 21433233280.

The previous prime is 21433233257. The next prime is 21433233287. The reversal of 21433233281 is 18233233412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20386128400 + 1047104881 = 142780^2 + 32359^2 .

It is a cyclic number.

It is not a de Polignac number, because 21433233281 - 2³⁰ = 20359491457 is a prime.

It is a super-2 number, since 2×21433233281² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21433233287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10716616640 + 10716616641.

It is an arithmetic number, because the mean of its divisors is an integer number (10716616641).

Almost surely, 2^21433233281 is an apocalyptic number.

It is an amenable number.

21433233281 is a deficient number, since it is larger than the sum of its proper divisors (1).

21433233281 is an equidigital number, since it uses as much as digits as its factorization.

21433233281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20736, while the sum is 32.

Adding to 21433233281 its reverse (18233233412), we get a palindrome (39666466693).

The spelling of 21433233281 in words is "twenty-one billion, four hundred thirty-three million, two hundred thirty-three thousand, two hundred eighty-one".